1. Field of the Invention
The present invention relates to an incubator having a culture space for accommodating a cultured object such as a cell being cultivated, it particularly relates to an incubator supplying CO2 gas, N2 gas, water for humidification and so on through a filter, and it relates to a method for decontaminating the incubator.
2. Description of the Related Art
In an incubator, in which cultivation is carried out with accommodating cells, microbes, and so on in a culture space, it is necessary to decontaminate the inside of the incubator and create an aseptic condition before accommodating the cells and so on in the culture space. Thus, decontamination gas such as hydrogen peroxide gas (H2O2 gas) is introduced from a decontamination gas supply device into the culture space to decontaminate and maintain an aseptic environment inside of the culture space.
In an incubator used for cultivating cells and so on, carbon dioxide gas (CO2 gas) or nitrogen gas (N2 gas) having a predetermined concentration is supplied into the culture space provided in the incubator in order to create a suitable environment in the culture space for cell cultivation (see Japanese Patent No. 4799221), and water for humidification is supplied into the culture space in order to maintain the inside of the culture space at a constant humidity (see Japanese Unexamined Patent Publication No. 2011-160672).
A sterilization filter is provided in supply passages, through which CO2 gas, N2 gas, and water for humidification or the like (hereinafter, these are referred to as the environment-adjusting-media) are supplied to the culture space, so that the environment-adjusting-media are supplied through the filters. Further, for maintaining the sterilization of the culture space, these filters should be sterilized.
In a device disclosed in Japanese Patent No. 4799221, the sterilization of the inside of the cultivation space of the incubator is carried out at the same time when the inside of a chamber of the isolator is sterilized. Namely, the decontamination gas is introduced from the isolator into the incubator by opening the door between the isolator and the incubator. At this time, the decontamination gas in the culture space is sucked from a sampling pipe, and introduced to pipes for supplying CO2 gas and N2 gas through branching pipes, to sterilize filters provided in the supply pipes.
In a device disclosed in Japanese Unexamined Patent Publication No. 2011-160672, the decontamination gas is sucked from the culture space to a water supply passage to decontaminate the filters. Therefore, it is not necessary to provide a pipe such as a sampling pipe. However, in such a construction, a filter sterilized by the decontamination gas can only be irradiated by ultraviolet rays using an ultraviolet lamp, so that the decontamination gas is sterilized.
In a device disclosed in Japanese Patent No. 4799221, a sampling circuit is utilized for decontamination of filters provided in supply pipes for CO2 gas and N2 gas. In the case of an incubator, which does not need to be provided with such a sampling circuit, pipes corresponding to the sampling circuit should be separately provided for sterilization, which increases the cost. Further, in a device disclosed in Japanese Unexamined Patent Publication No. 2011-160672, since the decontamination gas on the sterilized filters is only sterilized by using an ultraviolet lamp, H2O2 gas remains on the sterilized filters. If water for humidification is supplied to the filters, H2O2 gas is mixed with the water for humidification, and H2O2 gas can get mixed in with the moisture supplied into the culture space, which can destroy the culture environment.